1. Field of the Invention
The present invention relates to a ground fault circuit interrupter. More specifically, the present invention relates to a ground fault circuit interrupter with end-of-life protection.
2. Description of the Related Art
With the increasing use of household electrical appliances, people demand that receptacles installed in their houses be capable of protecting them from serious injury when accidentally touched or other ground fault conditions occur. Thus, ground fault circuit interrupters (“GFCI devices”) are designed to break the electrical continuity upon detecting a ground fault condition occurring at an alternating current (“AC”) load.
Many electrical wiring devices including receptacles have a line side that is connectable to an electrical power supply, and a load side that is connectable to one or more loads and at least one conductive path between the line side and load side. When a person accidentally comes in contact with the line side of the AC load and an earth ground at the same time, a serious injury may occur because the human body forms another conductive path for the electrical current to flow through. There is a strong desire for electrical wiring devices that can break electric power supply to various loads such as household appliances and consumer electronic products when a ground fault condition occurs.
The GFCI devices can detect a ground fault condition and break the electric power supply by employing a sensing transformer to detect an imbalance between the currents flowing in the phase (also known as “hot”) and neutral conductive paths of the power supply. A ground fault condition happens when the current is diverted to the ground through another path such as a human body, that results in an imbalance between the currents flowing in the phase and neutral conductors. Upon detection of a ground fault condition, a breaker within the GFCI devices is immediately tripped to interrupt the electrical continuity and removes all power supply to the loads.
However, a GFCI device may reach the end of its life and cannot function properly to break the power supply after detecting a ground fault condition. Consumers are endangered if they are not aware that the GFCI device has reached the end of its life and continue to use it.